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Groups > linux.kernel > #1226096

RE: tools: usbip: detach: avoid calling strlen() at each iteration

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From: Aaro Koskinen
> Sent: 15 September 2015 21:56
...
> > -	for (unsigned int i = 0; i < strlen(port); i++)
> > +	unsigned int port_len = strlen(port);
> > +
> > +	for (unsigned int i = 0; i < port_len; i++)
> 
> port is read only in this function, so maybe just use "const" and the
> compiler should know to do the same without adding a new variable?

While I've seen the compiler make the assumption, I'm not sure
it should assume that data that is 'const' in one function cannot
be modified by a called function.
(Unless the compiler has some way of knowing that the called function
cannot obtain a non-const pointer to the referenced data.)
(This is also independent of whether the const pointer is passed
to the function.) 

	David

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tools: usbip: detach: avoid calling strlen() at each iteration Eric Curtin <ericcurtin17@gmail.com> - 2015-09-15 22:30 +0200
  Re: tools: usbip: detach: avoid calling strlen() at each iteration Aaro Koskinen <aaro.koskinen@iki.fi> - 2015-09-15 23:10 +0200
    Re: tools: usbip: detach: avoid calling strlen() at each iteration Clemens Ladisch <clemens@ladisch.de> - 2015-09-16 09:40 +0200
    RE: tools: usbip: detach: avoid calling strlen() at each iteration David Laight <David.Laight@ACULAB.COM> - 2015-09-16 15:50 +0200

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